The invention concerns processes for the cold mechanical working of metallic materials below their recrystallization temperatures, preferably at room temperature.
The invention more particularly relates to extrusion and drawing of wires, profiles, tubes and sheets, and those systems in which hydrodynamic lubrication prevents direct contact between the material being mechanically worked and the forming apparatus.
For the drawing of metallic materials, solid, partially-solidified or liquid lubricants are used. As liquid lubricants, alkali stearates among others in aqueous solution are known. These lubricants are either lead to the drawing hole as liquids or applied to the material to be worked, dried and then transported with the material to the drawing hole. These lubricants exhibit relatively low dynamic viscosities and are therefore not suitable for the mechanically treating of materials with high tensile strength. Thus, for example, sodium stearate can only be used with materials whose tensile strengths are less than about 1000 N/mm.sup.2.
In addition, a continuous process with multistage mechanical working is difficult to achieve, on account of the solvent in the lubricant with a boiling point of 100.degree. C. The drying requires considerable time and much technical outlay, as the dynamic viscosity of the lubricant is reduced when it is insufficiently dry.
Moreover, it is a disadvantage of the prior art processes that the lubricant does not act to dissolve fats, so that under the operating parameters a degreasing pretreatment of the material is necessary.